Lifting hook, safety latch of lifting hook and locking and releasing device of safety latch

Abstract

A lifting hook, its safety latch and a locking and releasing device of the safety latch are disclosed. The lifting hook includes a hook body having a hook stem and tip. The safety latch is pivotably fastened close to the stem so as to move the safety latch between an open position and a closed position, the safety latch being in its open position substantially against the inside of the hook body in a position that leaves a hook jaw free, while in the closed position a latch end extends across the hook jaw to the hook tip, closing the jaw on the inside thereof. The locking and releasing device of the safety latch includes a locking element that engages the inner surface area of the hook jaw at a distance below the fastening end of the safety latch, and a releasing lever that when turned, releases the locking element.

The invention claimed is: 
     
       1. A lifting hook comprising:
 a hook body with a hook stem and a hook tip; 
 a safety latch with a fastening end and a free latch end, the fastening end of the safety latch being pivotably fastened close to the hook stem so as to move the safety latch between an open position and a closed position, the safety latch being in its open position substantially against the inside of the hook body in a position that leaves a hook jaw free, while in the closed position of the safety latch, the latch end extends substantially across the hook jaw to the hook tip and against the hook tip, resting against the inside of the hook body and the hook jaw, closing the hook jaw; and 
 an actuator configured to actuate the safety latch, the actuator comprising:
 a spring arranged between the safety latch and the hook body and forcing the latch end into the closed position; and 
 a locking and releasing device for locking the safety latch into the open position and for releasing the safety latch from the open position, wherein the locking and releasing device comprises a locking element arranged on the back surface of the safety latch, and wherein the locking element in a locking position against the surface of the hook body engages the inner surface area of the hook jaw at a distance below the fastening end of the safety latch; and 
 a releasing lever that extends to the front side of the safety latch and is fastened to the locking element and to the safety latch and, when turned, releases the locking element and, thus, allows the safety latch to turn into its closed position, 
 
 wherein the releasing lever is pivotably arranged to a mounting frame that is fastened to the back surface of the safety latch. 
 
     
     
       2. The lifting hook as claimed in  claim 1 , wherein the locking element comprises a locking magnet with a locking surface that in the locking position engages the surface of the hook body and locks the safety latch into the open position. 
     
     
       3. The lifting hook as claimed in  claim 2 , wherein the releasing lever is fastened to the locking magnet, whereby when the releasing lever is turned, the releasing lever also turns the locking magnet and releases the locking magnet from the locking position and, thus, allows the safety latch to turn to the closed position. 
     
     
       4. The lifting hook as claimed in  claim 2 , wherein the mounting frame comprises a base part that is fastened to the back surface of the safety latch, and two flanges rising from the sides of the base part, to which the releasing lever is mounted in such a manner that the locking magnet is between the flanges. 
     
     
       5. The lifting hook as claimed in  claim 2 , wherein the mounting frame comprises a base part that is fastened to the back surface of the safety latch, and that to the base part, a height-adjustable fastening is arranged for the releasing lever and the locking magnet fastened to it. 
     
     
       6. The lifting hook as claimed in  claim 5 , wherein the height-adjustable fastening comprises:
 a first U-shaped loop that is pivotably mounted from a middle part thereof to one end of the base part; and 
 a second U-shaped loop that is pivotably mounted from a middle part thereof to the other end of the base part, 
 wherein lead-through openings are formed at the ends of branches of the first and second U-shaped loops, through which the releasing lever is guided in such a manner that the U-shaped loops and the releasing lever form together a working entity, 
 wherein the locking magnet is between the ends of the branches, and 
 wherein the fastening of the first U-shaped loop to the mounting frame is made adjustable in distance relative to the corresponding fastening of the second U-shaped loop. 
 
     
     
       7. The lifting hook as claimed in  claim 6 , wherein the adjustable fastening of the first and second U-shaped loops comprises:
 an adjustment carriage structure that is fastened to the base part and comprises an adjustment carriage frame; 
 an adjustment carriage mounted slidably on the adjustment carriage frame, and 
 an adjustment screw arranged on the adjustment carriage and adjustment carriage frame for adjusting the position of the adjustment carriage and, thus, for adjusting the elevation of the releasing lever and the locking magnet fastened to releasing lever in relation to the base part. 
 
     
     
       8. The lifting hook as claimed in  claim 1 , wherein the releasing lever is in an L-shaped configuration. 
     
     
       9. A lifting hook comprising:
 a hook body with a hook stem and a hook tip; 
 a safety latch with a fastening end and a free latch end, the fastening end of the safety latch being pivotably fastened close to the hook stem so as to move the safety latch between an open position and a closed position, the safety latch being in its open position substantially against the inside of the hook body in a position that leaves a hook jaw free, while in the closed position of the safety latch, the latch end extends substantially across the hook jaw to the hook tip and against the hook tip, resting against the inside of the hook body and the hook jaw, closing the hook jaw; and 
 an actuator configured to actuate the safety latch, the actuator comprising:
 a spring arranged between the safety latch and the hook body and forcing the latch end into the closed position; and 
 a locking and releasing device for locking the safety latch into the open position and for releasing the safety latch from the open position, wherein the locking and releasing device comprises a locking element arranged on the back surface of the safety latch, and wherein the locking element in a locking position against the surface of the hook body engages the inner surface area of the hook jaw at a distance below the fastening end of the safety latch; and 
 
 a releasing lever that extends to the front side of the safety latch and is fastened to the locking element and to the safety latch and, when turned, releases the locking element and, thus, allows the safety latch to turn into its closed position, 
 wherein the locking element comprises a locking magnet with a locking surface that in the locking position engages the surface of the hook body and locks the safety latch into the open position, and 
 wherein the releasing lever forms a closed loop having a back part that extends to the back side of the safety latch, serves as the fastening for the locking magnet and has side branches extending to both sides of the safety latch, and a front part that extends to the front side of the safety latch, comes into contact with the load being lifted and has side branches extending to both sides thereof and connecting to the side branches of the back part. 
 
     
     
       10. A safety latch configured to be attached to a lifting hook comprising a hook body with a hook jaw, a hook stem and a hook tip, the safety latch comprising:
 fastening end and a free latch end, the fastening end is configured to be pivotably fastened close to the hook stem so as to move the safety latch between an open position and a closed position, the safety latch configured to be in its open position substantially against the inside of the hook body in a position that leaves the hook jaw free, and while in the closed position of the safety latch, the latch end is configured to extend substantially across the hook jaw to the hook tip and against the hook tip, resting against the inside of the hook body and the hook jaw, closing the hook jaw; and 
 an actuator configured to actuate the safety latch, the actuator comprising:
 a spring is configured to be arranged between the safety latch and the hook body and forcing the latch end into the closed position; and 
 a locking and releasing device configured to lock the safety latch into the open position and to release the safety latch from the open position, wherein the locking and releasing device comprises a locking element arranged on the back surface of the safety latch, and wherein the locking element is configured to in a locking position against the surface of the hook body engage the inner surface area of the hook jaw at a distance below the fastening end of the safety latch; and 
 a releasing lever that extends to the front side of the safety latch and is fastened to the locking element and to the safety latch and, when turned, releases the locking element and, thus, allows the safety latch to turn into its closed position, 
 
 wherein the releasing lever is pivotably arranged to a mounting frame that is fastened on the back surface of the safety latch. 
 
     
     
       11. The safety latch as claimed in  claim 10 , wherein the locking element comprises a locking magnet with a locking surface that in the locking position is configured to engage the surface of the hook body and to lock the safety latch into the open position. 
     
     
       12. The safety latch as claimed in  claim 11 , wherein the releasing lever is fastened to the locking magnet, whereby when the releasing lever is turned, the releasing lever also turns the locking magnet and releases the locking magnet from the locking position and, thus, allows the safety latch to turn to the closed position. 
     
     
       13. The safety latch as claimed in  claim 11 , wherein the mounting frame comprises a base part that is fastened to the back surface of the safety latch, and two flanges rising from the sides of the base part, to which the releasing lever is mounted in such a manner that the locking magnet is between the flanges. 
     
     
       14. The safety latch as claimed in  claim 11 , wherein the mounting frame comprises a base part that is fastened to the back surface of the safety latch, and that to the base part, a height-adjustable fastening is arranged for the releasing lever and the locking magnet fastened to the releasing lever. 
     
     
       15. The safety latch as claimed in  claim 14 , wherein the height-adjustable fastening comprises:
 a first U-shaped loop that is pivotably mounted from a middle part thereof to one end of the base part; and 
 a second U-shaped loop that is pivotably mounted from a middle part thereof to the other end of the base part, 
 wherein lead-through openings are formed at the ends of branches of the first and second U-shaped loops, through which the releasing lever is guided in such a manner that the U U-shaped loops and the releasing lever form together a working entity, 
 wherein the locking magnet is between the ends of the branches, and 
 wherein the fastening of one the first U-shaped loop to the mounting frame is made adjustable in distance relative to the corresponding fastening of the second U-shaped loop. 
 
     
     
       16. The safety latch as claimed in  claim 15 , wherein the adjustable fastening of the first and second U-shaped loops comprises:
 an adjustment carriage structure that is fastened to the base part and comprises an adjustment carriage frame; 
 an adjustment carriage mounted slidably on the adjustment carriage frame; and 
 an adjustment screw arranged on the adjustment carriage and adjustment carriage frame for adjusting the position of the adjustment carriage and, thus, for adjusting the elevation of the releasing lever and the locking magnet fastened to releasing lever in relation to the base part. 
 
     
     
       17. The safety latch as claimed in  claim 10 , wherein the locking and releasing device is designed to be fastened by adhesive, glue or one or more screws on the back surface of the safety latch. 
     
     
       18. A safety latch configured to be attached to a lifting hook comprising a hook body with a hook jaw, a hook stem and a hook tip, the safety latch comprising:
 a fastening end and a free latch end, the fastening end is configured to be pivotably fastened close to the hook stem so as to move the safety latch between an open position and a closed position, the safety latch configured to be in its open position substantially against the inside of the hook body in a position that leaves the hook jaw free, and while in the closed position of the safety latch, the latch end is configured to extend substantially across the hook jaw to the hook tip and against the hook tip, resting against the inside of the hook body and the hook jaw, closing the hook jaw; and 
 an actuator configured to actuate the safety latch, the actuator comprising:
 a spring is configured to be arranged between the safety latch and the hook body and forcing the latch end into the closed position; and 
 a locking and releasing device configured to lock the safety latch into the open position and to release the safety latch from the open position, wherein the locking and releasing device comprises a locking element arranged on the back surface of the safety latch, and wherein the locking element is configured to in a locking position against the surface of the hook body engage the inner surface area of the hook jaw at a distance below the fastening end of the safety latch; and 
 
 a releasing lever that extends to the front side of the safety latch and is fastened to the locking element and to the safety latch and, when turned, releases the locking element and, thus, allows the safety latch to turn into its closed position, 
 wherein the locking element comprises a locking magnet with a locking surface that in the locking position is configured to engage the surface of the hook body and to lock the safety latch into the open position, and 
 wherein the releasing lever forms a closed loop having a back part that extends to the back side of the safety latch, serves as the fastening for the locking magnet and has side branches extending to both sides of the safety latch, and a front part that extends to the front side of the safety latch, comes into contact with the load being lifted and has side branches extending to both sides thereof and connecting to the side branches of the back part.